bevy/crates/bevy_ui/Cargo.toml
Antony bf42cb3532
Add a viewport UI widget (#17253)
# Objective

Add a viewport widget.

## Solution

- Add a new `ViewportNode` component to turn a UI node into a viewport.
- Add `viewport_picking` to pass pointer inputs from other pointers to
the viewport's pointer.
- Notably, this is somewhat functionally different from the viewport
widget in [the editor
prototype](https://github.com/bevyengine/bevy_editor_prototypes/pull/110/files#L124),
which just moves the pointer's location onto the render target. Viewport
widgets have their own pointers.
  - Care is taken to handle dragging in and out of viewports.
- Add `update_viewport_render_target_size` to update the viewport node's
render target's size if the node size changes.
- Feature gate picking-related viewport items behind
`bevy_ui_picking_backend`.

## Testing

I've been using an example I made to test the widget (and added it as
`viewport_node`):

<details><summary>Code</summary>

```rust
//! A simple scene to demonstrate spawning a viewport widget. The example will demonstrate how to
//! pick entities visible in the widget's view.

use bevy::picking::pointer::PointerInteraction;
use bevy::prelude::*;

use bevy::ui::widget::ViewportNode;
use bevy::{
    image::{TextureFormatPixelInfo, Volume},
    window::PrimaryWindow,
};
use bevy_render::{
    camera::RenderTarget,
    render_resource::{
        Extent3d, TextureDescriptor, TextureDimension, TextureFormat, TextureUsages,
    },
};

fn main() {
    App::new()
        .add_plugins((DefaultPlugins, MeshPickingPlugin))
        .add_systems(Startup, test)
        .add_systems(Update, draw_mesh_intersections)
        .run();
}

#[derive(Component, Reflect, Debug)]
#[reflect(Component)]
struct Shape;

fn test(
    mut commands: Commands,
    window: Query<&Window, With<PrimaryWindow>>,
    mut images: ResMut<Assets<Image>>,
    mut meshes: ResMut<Assets<Mesh>>,
    mut materials: ResMut<Assets<StandardMaterial>>,
) {
    // Spawn a UI camera
    commands.spawn(Camera3d::default());

    // Set up an texture for the 3D camera to render to
    let window = window.get_single().unwrap();
    let window_size = window.physical_size();
    let size = Extent3d {
        width: window_size.x,
        height: window_size.y,
        ..default()
    };
    let format = TextureFormat::Bgra8UnormSrgb;
    let image = Image {
        data: Some(vec![0; size.volume() * format.pixel_size()]),
        texture_descriptor: TextureDescriptor {
            label: None,
            size,
            dimension: TextureDimension::D2,
            format,
            mip_level_count: 1,
            sample_count: 1,
            usage: TextureUsages::TEXTURE_BINDING
                | TextureUsages::COPY_DST
                | TextureUsages::RENDER_ATTACHMENT,
            view_formats: &[],
        },
        ..default()
    };
    let image_handle = images.add(image);

    // Spawn the 3D camera
    let camera = commands
        .spawn((
            Camera3d::default(),
            Camera {
                // Render this camera before our UI camera
                order: -1,
                target: RenderTarget::Image(image_handle.clone().into()),
                ..default()
            },
        ))
        .id();

    // Spawn something for the 3D camera to look at
    commands
        .spawn((
            Mesh3d(meshes.add(Cuboid::new(5.0, 5.0, 5.0))),
            MeshMaterial3d(materials.add(Color::WHITE)),
            Transform::from_xyz(0.0, 0.0, -10.0),
            Shape,
        ))
        // We can observe pointer events on our objects as normal, the
        // `bevy::ui::widgets::viewport_picking` system will take care of ensuring our viewport
        // clicks pass through
        .observe(on_drag_cuboid);

    // Spawn our viewport widget
    commands
        .spawn((
            Node {
                position_type: PositionType::Absolute,
                top: Val::Px(50.0),
                left: Val::Px(50.0),
                width: Val::Px(200.0),
                height: Val::Px(200.0),
                border: UiRect::all(Val::Px(5.0)),
                ..default()
            },
            BorderColor(Color::WHITE),
            ViewportNode::new(camera),
        ))
        .observe(on_drag_viewport);
}

fn on_drag_viewport(drag: Trigger<Pointer<Drag>>, mut node_query: Query<&mut Node>) {
    if matches!(drag.button, PointerButton::Secondary) {
        let mut node = node_query.get_mut(drag.target()).unwrap();

        if let (Val::Px(top), Val::Px(left)) = (node.top, node.left) {
            node.left = Val::Px(left + drag.delta.x);
            node.top = Val::Px(top + drag.delta.y);
        };
    }
}

fn on_drag_cuboid(drag: Trigger<Pointer<Drag>>, mut transform_query: Query<&mut Transform>) {
    if matches!(drag.button, PointerButton::Primary) {
        let mut transform = transform_query.get_mut(drag.target()).unwrap();
        transform.rotate_y(drag.delta.x * 0.02);
        transform.rotate_x(drag.delta.y * 0.02);
    }
}

fn draw_mesh_intersections(
    pointers: Query<&PointerInteraction>,
    untargetable: Query<Entity, Without<Shape>>,
    mut gizmos: Gizmos,
) {
    for (point, normal) in pointers
        .iter()
        .flat_map(|interaction| interaction.iter())
        .filter_map(|(entity, hit)| {
            if !untargetable.contains(*entity) {
                hit.position.zip(hit.normal)
            } else {
                None
            }
        })
    {
        gizmos.arrow(point, point + normal.normalize() * 0.5, Color::WHITE);
    }
}
```

</details>

## Showcase


https://github.com/user-attachments/assets/39f44eac-2c2a-4fd9-a606-04171f806dc1

## Open Questions

- <del>Not sure whether the entire widget should be feature gated behind
`bevy_ui_picking_backend` or not? I chose a partial approach since maybe
someone will want to use the widget without any picking being
involved.</del>
- <del>Is `PickSet::Last` the expected set for `viewport_picking`?
Perhaps `PickSet::Input` is more suited.</del>
- <del>Can `dragged_last_frame` be removed in favor of a better dragging
check? Another option that comes to mind is reading `Drag` and `DragEnd`
events, but this seems messier.</del>

---------

Co-authored-by: ickshonpe <david.curthoys@googlemail.com>
Co-authored-by: François Mockers <mockersf@gmail.com>
2025-05-05 22:57:37 +00:00

67 lines
2.4 KiB
TOML

[package]
name = "bevy_ui"
version = "0.16.0-dev"
edition = "2024"
description = "A custom ECS-driven UI framework built specifically for Bevy Engine"
homepage = "https://bevyengine.org"
repository = "https://github.com/bevyengine/bevy"
license = "MIT OR Apache-2.0"
keywords = ["bevy"]
[dependencies]
# bevy
bevy_a11y = { path = "../bevy_a11y", version = "0.16.0-dev" }
bevy_app = { path = "../bevy_app", version = "0.16.0-dev" }
bevy_asset = { path = "../bevy_asset", version = "0.16.0-dev" }
bevy_color = { path = "../bevy_color", version = "0.16.0-dev" }
bevy_core_pipeline = { path = "../bevy_core_pipeline", version = "0.16.0-dev" }
bevy_derive = { path = "../bevy_derive", version = "0.16.0-dev" }
bevy_ecs = { path = "../bevy_ecs", version = "0.16.0-dev" }
bevy_image = { path = "../bevy_image", version = "0.16.0-dev" }
bevy_input = { path = "../bevy_input", version = "0.16.0-dev" }
bevy_math = { path = "../bevy_math", version = "0.16.0-dev" }
bevy_reflect = { path = "../bevy_reflect", version = "0.16.0-dev" }
bevy_render = { path = "../bevy_render", version = "0.16.0-dev" }
bevy_sprite = { path = "../bevy_sprite", version = "0.16.0-dev" }
bevy_text = { path = "../bevy_text", version = "0.16.0-dev" }
bevy_picking = { path = "../bevy_picking", version = "0.16.0-dev", optional = true }
bevy_transform = { path = "../bevy_transform", version = "0.16.0-dev" }
bevy_window = { path = "../bevy_window", version = "0.16.0-dev" }
bevy_utils = { path = "../bevy_utils", version = "0.16.0-dev" }
bevy_platform = { path = "../bevy_platform", version = "0.16.0-dev", default-features = false, features = [
"std",
] }
# other
taffy = { version = "0.7" }
serde = { version = "1", features = ["derive"], optional = true }
uuid = { version = "1.1", features = ["v4"], optional = true }
bytemuck = { version = "1.5", features = ["derive"] }
thiserror = { version = "2", default-features = false }
derive_more = { version = "1", default-features = false, features = ["from"] }
nonmax = "0.5"
smallvec = "1.11"
accesskit = "0.18"
tracing = { version = "0.1", default-features = false, features = ["std"] }
[features]
default = []
serialize = [
"serde",
"smallvec/serde",
"bevy_math/serialize",
"bevy_platform/serialize",
]
bevy_ui_picking_backend = ["bevy_picking", "dep:uuid"]
bevy_ui_debug = []
# Experimental features
ghost_nodes = []
[lints]
workspace = true
[package.metadata.docs.rs]
rustdoc-args = ["-Zunstable-options", "--generate-link-to-definition"]
all-features = true